Ultrasound Assessment of Disease Activity After Knee Joint Surgery in Eight Patients with Rheumatoid Arthritis

Abstract

Objective: Ultrasound assessment is considered a useful method for detecting synovitis in patients with rheumatoid arthritis (RA) due to its greater sensitivity compared with a clinical joint examination. The purpose of this study was to investigate the effectiveness of ultrasound assessment after knee joint surgery in patients with RA.

Methods: We evaluated eight patients with RA (7 females and 1 male; average age of 56 years) who underwent total knee arthroplasty (n=4) or arthroscopic knee synovectomy (n=4). Ultrasound assessment was performed at baseline and at one, three, and six months after knee joint surgery in 26 upper limb and 16 lower limb joints, respectively. Ultrasonographic arthritis was defined as ultrasound-detected synovitis with a gray scale (GS) imaging score≥2 and a power Doppler (PD) signal score≥1. The disease activity score including C-reactive protein (DAS28-CRP (4)) was also evaluated at baseline and at one, three, and six months after surgery.

Results: In all cases, the DAS28-CRP (4) improved from 3.72±1.16 at baseline to 2.51±0.70 at 3 months after surgery. There were also decreases from baseline to three months after surgery in the number of joints with ultrasonographic arthritis (4.9±5.2 to 0.7±0.8), total GS score (10.0±14.2 to 4.1±5.6), and PD score (8.4±15.3 to 2.0±3.6). However, these values had slightly increased at six months after knee joint surgery.

Conclusion: Objective ultrasound assessment detected improvement of arthritis at three months, but with relapse at six months after surgery. Thus, ultrasound scanning can more accurately evaluate RA disease activity after knee joint surgery.